Coloring matter of the phthalocyanine type



Patented June 16, 1942 Isidor Morris Heilbron, London, Francis Irving,Manchester, England, and Reginald Patrick Linstead, Cambridge, Mass.,assignors to Imperial Chemical Industries Limited, a corporation ofGreat Britain No Drawing. Original application October 6,

1938, Serial No. 232",602. Divided and this applicationMay 18, 1940,Serial No. 336,002. In Great Br-itain November 16, 1932 3 Claims.

This application relates tocoloring matters of the phthalocyanineseries, and constitutes "a division of our copending "application SerialNo. 233,602, filed October 6, 1938 (Patent No. 2,242,301), which in turn"is adivision of our earlier application Serial No. 79,813 (Patent No.2,166,213) and derives priority 'from "our former application Serial No.698,216, filed November 15, 1933, and issued -May 10, 1938, as PatentNo. 2,116,602.

It is an object of this invention 'to'pro'vide an improved process forthe manufacture of coloring matters of the phthalocy'anine series,especially those which contain combined'copper, and which willhereinafter be referred "to as copper phthalocyanines. It is 'a furtherobject of this invention to provide a process'for the production ofcopper phthalocyanines which leads to a product of high purity. -It-is afurtherobject of this invention toproduce copper phthalocyanines ofextremely high quality, and which are superior in chemical purity andcoloring properties to the product obtainable by heating phthalicanhydride or phthalimide in the presence of copper compounds. Other andfurther important objects of this invention will appear as thedescription proceeds.

We have found that coloring matters of the phthalocyanine series, ofimproved properties, can be obtained by heating an o-arylene dicyanide,for instance phthalonitrile, with copper or copper compounds in theabsence of a base or in the absence of any solvent whatever.

We have also found that substituted phthalonitriles and o-dinitriles ofnaphthalene and anthracene may be used instead of phthalom'trile. Theso-obtained coloring matters are typically blue to green in shade, haveonly slight solubility in organic solvents, but dissolve in concentratedsulfuric acid and are decomposed by nitric acid. They contain nitrogen,are of complex constitution and contain copper in combined form. Theirtypical constitution is illustrated by the compound derived fromphthalonitrile, which corresponds to the empirical formula (CsH4N2)4C1l,

and has a structure which is most probably represented by the followingformula:

It will be understood, however, that the above formula is notlimitative, and does not exclude the possibility of other, especiallytautomeric, arrangements.

The copper-containing coloring matters from substituted phthalonitrilesand copper or copper compounds appear to be substituted derivatives ofthe above.

Combination is preferably effected by submitting the o-arylene dicyanideto the action of heat in the presence of a cupriferous reagent, such asmetallic copper, or cuprous or cupric compounds. Particularly valuableembodiments of this process are the manufacture of coloring matters byheating phthalonitril'e with copper or copper compounds in the absenceof any solvent whatever or in the presence of a non-basic, high-boilingorganic diluent such as naphthalene or alphachloro-naphthalene.

Working according to this new process the coloring matters are,generally speaking, formed with greater readiness than according tothose of British Patent Specifications Nos. 322,169, 389,842 and390,149, and higher yields, in some cases nearly the theoretical, areobtained. Purification may be effected as already described in the saidspecification.

The coloring matters may be employed as pigments. For instance, they maybe made into lakes with the usual substrata. Such lakes may be used ascoloring matters for varnishes and inks.

The following examples in which parts are by weight illustrate but donot limit the invention.

Example 1 A mixture of 12.8 parts of phthalonitrile and 2.5 parts ofcuprous chloride is heated gently in a stream of nitrogen. A vigorousreaction takes place and after a few minutes, the mass becomes almostsolid. This mass is allowed to cool, broken and extracted with boilingwater. After filtering the residue is boiled successively with diluteacid, and alcohol, filtered after each boiling and finally washed withwater and dried. The resulting bright blue pigment appears to possessthe same properties as copper-phthalocyanine. It does contain, however,combined chlorine, and apparently consists of a mixture of thecopperphthalocyanine proper, (C8H4N2)4Cu, and of a chlorinatedderivative thereof. The latter is more fully identified and claimed inU. S. Patent No. 2,129,013 of Linstead and Dent, issued September 6,1938. V

In lieu of copper and cuprous chloride, one

may employ cuprous cyanide, cuprous and cupric oxides, cupric sulfide,cupric chloride, cupric acetate and cupric sulfate. Indeed, we believethat any compound of copper which is capable of yielding coppercompounds when reacted for instance with an acid will give thecopper-phthalocyanine if heated with phthalonitrile at suitabletemperatures in a suitable medium. When cupric chloride is used theresulting pigment contains chlorine, but otherwise appears to have thesame structure as copper-phthalocyanine.

Example 2 3-nitrophthalonitrile made from 3-nitrophthalic acid byheating with urea to give the imide, heating this with ammonia to givethe diamide, and boiling the diamide with acetic anhydride) and copperbronze are heated to 220 C. in methyl-naphthalene. The methylnaphthaleneis removed and the residue purified with concentrated sulfuric acid. Agood yield of pigment is obtained and this appears to be a tetranitroderivative of the copper compound formulated above. Its empiricalformula is therefore [CBH3(NO2)N2]4CU., and considering its mode ofsynthesis it must be concluded that the four nitro groups therein areuniformly distributed over the four phenylene nuclei. The exact positionof the nitro group in each phenylene nucleus cannot be stated withcertainty, in view of the possibility of cisand trans-orientation ofeach 3-nitrophthalonitrile radical as it takes its position in thephthalocyanine complex. But the relative position of the nitro groupwith respect to the extran'uclear carbon atoms (that is, the carbonatoms of the CN groups in the initial material) may be presumed to bethe same as in theparent material. The product of this example thereforewill have one nitro group in each phenylene nucleus in ortho-position tothe nearest extranuclear car- -bon atom.

also readily gives a coloring matter containing copper. The orientationof the nitro group in each phenylene nucleus must be presumed here to bein meta position to the nearest extranuclear carbon atom.

It will be understood that our invention is susceptible of widevariation and modification without departing from the spirit thereof, asdefined by the subjoined claims.

We claim: I 7 v 1. A tetranitro-copper-phthalocyanine corresponding inconstitution to the empirical formula [CsHa(N02)N2]4Cu, and in which thefour nitro groups are uniformly distributed over the four phenylenenuclei of the phthalocyanine complex.

2. A tetranitro-copper-phthalocyanine as de fined in claim 1, whereinthe nitro group in each nucleus is situated ortho to the nearest extranuclear carbon atom. v

3. A tetranitro-copper-phthalocyanine as defined in claim 1, wherein thenitro group in each nucleus is situated meta to the nearest extranuclearcarbon atom.

ISIDQR MORRIS HEILBRON.

FRANCIS IIRVHTG; REGINALD PATRICK LINSTEAD.

